From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965044Ab2COCSE (ORCPT ); Wed, 14 Mar 2012 22:18:04 -0400 Received: from mx1.redhat.com ([209.132.183.28]:5517 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755757Ab2COCRo (ORCPT ); Wed, 14 Mar 2012 22:17:44 -0400 Date: Wed, 14 Mar 2012 22:17:39 -0400 From: Dave Jones To: paulmck@linux.vnet.ibm.com Cc: Linux Kernel Subject: list-debug variants of rcu list routines. Message-ID: <20120315021738.GA31213@redhat.com> Mail-Followup-To: Dave Jones , paulmck@linux.vnet.ibm.com, Linux Kernel MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Make __list_add_rcu check the next->prev and prev->next pointers just like __list_add does. * Make list_del_rcu use __list_del_entry, which does the same checking at deletion time. Has been running for a week here without anything being tripped up, but it seems worth adding for completeness just in case something ever does corrupt those lists. Signed-off-by: Dave Jones diff -durpN '--exclude-from=/home/davej/.exclude' -u src/git-trees/kernel/linux/include/linux/rculist.h linux-dj/include/linux/rculist.h --- src/git-trees/kernel/linux/include/linux/rculist.h 2011-07-23 00:05:34.000000000 -0400 +++ linux-dj/include/linux/rculist.h 2012-03-07 00:21:47.050583527 -0500 @@ -30,6 +30,7 @@ * This is only for internal list manipulation where we know * the prev/next entries already! */ +#ifndef CONFIG_DEBUG_LIST static inline void __list_add_rcu(struct list_head *new, struct list_head *prev, struct list_head *next) { @@ -38,6 +39,10 @@ static inline void __list_add_rcu(struct rcu_assign_pointer(list_next_rcu(prev), new); next->prev = new; } +#else +extern void __list_add_rcu(struct list_head *new, + struct list_head *prev, struct list_head *next); +#endif /** * list_add_rcu - add a new entry to rcu-protected list @@ -108,7 +113,7 @@ static inline void list_add_tail_rcu(str */ static inline void list_del_rcu(struct list_head *entry) { - __list_del(entry->prev, entry->next); + __list_del_entry(entry); entry->prev = LIST_POISON2; } diff -durpN '--exclude-from=/home/davej/.exclude' -u src/git-trees/kernel/linux/lib/list_debug.c linux-dj/lib/list_debug.c --- src/git-trees/kernel/linux/lib/list_debug.c 2011-02-19 12:00:40.000000000 -0500 +++ linux-dj/lib/list_debug.c 2012-03-07 00:18:12.108062540 -0500 @@ -8,6 +8,7 @@ #include #include +#include /* * Insert a new entry between two known consecutive entries. @@ -73,3 +74,24 @@ void list_del(struct list_head *entry) entry->prev = LIST_POISON2; } EXPORT_SYMBOL(list_del); + +/* + * RCU variants. + */ +void __list_add_rcu(struct list_head *new, + struct list_head *prev, struct list_head *next) +{ + WARN(next->prev != prev, + "list_add_rcu corruption. next->prev should be " + "prev (%p), but was %p. (next=%p).\n", + prev, next->prev, next); + WARN(prev->next != next, + "list_add_rcu corruption. prev->next should be " + "next (%p), but was %p. (prev=%p).\n", + next, prev->next, prev); + new->next = next; + new->prev = prev; + rcu_assign_pointer(list_next_rcu(prev), new); + next->prev = new; +} +EXPORT_SYMBOL(__list_add_rcu);